[LAU] Is ALSA using hrtimer?

[Grant]

>> I have hrtimer support compiled into my kernel, but when I watch 'top'
>> while music is playing I can see that 'timer' uses CPU cycles but
>> 'hrtimer' never does.  How can I find out if ALSA is using hrtimer?
>
> ALSA uses the sound card interrupt for timing.  The hrtimer is used only
> for MIDI playback and for sound cards without interrupts, such as the
> SuperH, i.MX, PC Speaker, and dummy devices.

Are you sure?  CONFIG_SND_HRTIMER says:

"ALSA uses the hrtimer as a precise timing source. The ALSA sequencer
code also can use this timing source."

Would ALSA use the sound card interrupt for timing with my USB DAC?

- Grant